# Mipmaps in OpenGL
**URL:** https://discourse.processing.org/t/mipmaps-in-opengl/42315
**Category:** Coding Questions
**Created:** [June 30, 2023, 12:23pm UTC](https://discourse.processing.org/t/mipmaps-in-opengl/42315 "2023-06-30T12:23:50Z")
**Posts on this page:** 3
**Page:** 1
### Author:  [@clankill3r](https://discourse.processing.org/u/clankill3r)
#### Post date: [June 30, 2023, 12:23pm UTC](https://discourse.processing.org/t/mipmaps-in-opengl/42315/1 "2023-06-30T12:23:50Z")
I have the following image:
And the following sketch:
```java
PImage img;
PGraphics big;
PGraphics small;
boolean from_big_pg = true;
void setup() {
size(320, 180, P2D);
img = loadImage("big.png");
big = createGraphics(1280, 720, P2D);
small = createGraphics(32, 18, P2D);
}
void draw() {
big.beginDraw();
big.image(img, 0, 0, big.width, big.height);
big.endDraw();
small.beginDraw();
small.image(from_big_pg ? big : img, 0, 0, small.width, small.height);
small.endDraw();
gl_nearest_for_texture(small);
image(small, 0, 0, 320, 180);
gl_linear_for_texture(small);
}
public void gl_nearest_for_texture(PImage image) {
PGL pgl = beginPGL();
Texture image_tex = ((PGraphicsOpenGL)g).getTexture(image);
pgl.bindTexture(PGL.TEXTURE_2D, image_tex.glName);
pgl.texParameteri(PGL.TEXTURE_2D, PGL.TEXTURE_MIN_FILTER, PGL.NEAREST);
pgl.texParameteri(PGL.TEXTURE_2D, PGL.TEXTURE_MAG_FILTER, PGL.NEAREST);
pgl.bindTexture(PGL.TEXTURE_2D, 0);
endPGL();
}
public void gl_linear_for_texture(PImage image) {
PGL pgl = beginPGL();
Texture image_tex = ((PGraphicsOpenGL)g).getTexture(image);
pgl.bindTexture(PGL.TEXTURE_2D, image_tex.glName);
pgl.texParameteri(PGL.TEXTURE_2D, PGL.TEXTURE_MIN_FILTER, PGL.LINEAR);
pgl.texParameteri(PGL.TEXTURE_2D, PGL.TEXTURE_MAG_FILTER, PGL.LINEAR);
pgl.bindTexture(PGL.TEXTURE_2D, 0);
endPGL();
}
```
This is the result with from\_big\_pg set to false:
and this when it is set to true:
I would like the second result to look like the first. I suspect I have to set something with the mipmaps but I’m stuck here. Does someone know why the downscale from the PGraphics looks so bad?
This is one of the attempts:
```java
public void gl_texParameter_min_mag(PImage image, int min, int mag) {
PGL pgl = beginPGL();
Texture image_tex = ((PGraphicsOpenGL)g).getTexture(image);
pgl.bindTexture(PGL.TEXTURE_2D, image_tex.glName);
pgl.texParameteri(PGL.TEXTURE_2D, PGL.TEXTURE_MIN_FILTER, min);
pgl.texParameteri(PGL.TEXTURE_2D, PGL.TEXTURE_MAG_FILTER, mag);
pgl.bindTexture(PGL.TEXTURE_2D, 0);
endPGL();
}
```
Then before `small.beginDraw()` I added `gl_texParameter_min_mag(big, PGL.LINEAR_MIPMAP_LINEAR, PGL.LINEAR);`
Now everything is black, so maybe this would work, but the mipmaps are not updated?
I don’t know, hope someone can help since this seems a bit advanced.
---
### Author:  [@clankill3r](https://discourse.processing.org/u/clankill3r)
#### Post date: [July 4, 2023, 10:31am UTC](https://discourse.processing.org/t/mipmaps-in-opengl/42315/2 "2023-07-04T10:31:59Z")
Ok I’m a bit further, I can use `gl_texture(in).usingMipmaps(true, 3);` and this fixes it.
But it does not work when the input comes from a video file…
```auto
public Texture gl_texture(PImage img) {
return ((PGraphicsOpenGL)g).getTexture(img);
}
```
---
### Author:  [@clankill3r](https://discourse.processing.org/u/clankill3r)
#### Post date: [February 13, 2024, 8:18pm UTC](https://discourse.processing.org/t/mipmaps-in-opengl/42315/3 "2024-02-13T20:18:52Z")
>
>
> I tried to isolate the problem, but if I get rid of the PGraphics for example th…e bug seems to disappear.
>
> If I run the below script I get:
>
> \
>
> \`\`\`java
> import processing.video.\*;
>
> PGraphics big;
> PGraphics small;
>
> boolean from\_big\_pg = true;
>
> Movie movie;
>
> void setup() {
> size(320, 180, P2D);
> movie = new Movie(this, "big.mp4");
> movie.loop();
>
> big = createGraphics(1280, 720, P2D);
> small = createGraphics(32, 18, P2D);
> }
>
> //void movieEvent(Movie m) {
> // m.read();
> //}
>
> void draw() {
>
> if (movie.available()) {
> movie.read();
> }
>
> // only works with \`void movieEvent(Movie m)\`
> // and not with \`if (movie.available())\` (it stays grey)
>
> gl\_texture(movie).usingMipmaps(true, 3);
> gl\_texture(big).usingMipmaps(true, 3);
> gl\_texture(small).usingMipmaps(true, 3);
>
> big.beginDraw();
> big.image(movie, 0, 0, big.width, big.height);
> big.endDraw();
>
>
> small.beginDraw();
> small.image(from\_big\_pg ? big : movie, 0, 0, small.width, small.height);
> small.endDraw();
>
> image(small, 0, 0, 320, 180);
> }
>
> public Texture gl\_texture(PImage img) {
> return ((PGraphicsOpenGL)g).getTexture(img);
> }
> \`\`\`
>
> If I comment out the following: (which is not what I want):
>
> \`\`\`java
> gl\_texture(movie).usingMipmaps(true, 3);
> gl\_texture(big).usingMipmaps(true, 3);
> gl\_texture(small).usingMipmaps(true, 3);
> \`\`\`
>
> Then it works again:
>
> \
>
> Now the interesting part:
>
> If I use:
>
> \`\`\`java
> void movieEvent(Movie m) {
> m.read();
> }
> \`\`\`
>
> Instead of:
>
> \`\`\`java
> if (movie.available()) {
> movie.read();
> }
> \`\`\`
>
> Then the \`usingMipmaps\` part works...
>
> (Also if the usingMipmaps is before \`if (movie.available()) {\` then there is a nullpointerException).
>
> The video file:
> https://github.com/processing/processing-video/assets/738650/f7a6ba31-b697-49fb-aeac-110823d0453d